Get Reactive With Project Reactor and Spring 5

Spring – the tool that is over 13 years pleases our hearts and eyes of customers. Despite this long history of development the project continues to follow the latest trends and provides to developers the awesome set of add-ons that simplify the daily life.

During this tech-talk, I would like to discuss delicacies which were cooked by developers from Pivotal and how Reactivity reflected on the 5th iteration of the framework.

Transcript

1. Get Reactive With Spring 5 And Project Reactor by Oleh Dokuka
2. • JSE at Levi9 • 6+ dev experience • Spring fan • Reactivity preacher /oleh.dokuka /OlegDokuka /OlehDokuka WHO AM I?
3. Agenda 1. Why Reactive? 2. Reactivity Generations 3. Reactive Streams 4. Project Reactor 5. Reactivity in Action (Project Reactor + Spring 5)
4. So, why Reactive?1
5. Requirements of Nowadays https://sites.psu.edu/luopassion2/2016/01/25/a-brief-history-of-the-internet-of-things-iot/
6. Lean resource management https://i.ytimg.com/vi/EiH1sJCDs9c/maxresdefault.jpg
7. Asynchrony http://www.cntraveler.com/story/the-main-reasons-your-passport-application-will-be-denied
8. Fault Tolerance
9. Powerful way of thinking http://www.wallpaperup.com/200710/pipes_cranes.html
10. Reactive-Manifesto2
11. Sounds Cool
12. Reactivity Generations 3
13. Handler Observer Java
14. Skill Knowledge Rx.NET
15. Akka RxJava
16. RxJava AkkaStreams
17. RxJava 2 AkkaStream Project Reactor Reactive Streams Specified
19. Reactive Streams4
20. What is the Purpose?
21. Backpressure
23. Common API
24. Publisher Subscriber
25. Publisher Subscriber public interface Publisher<T> { public void subscribe( Subscriber<? super T> s ); }
26. Publisher Subscriber public interface Subscriber<T> { public void onSubscribe(Subscription s); public void onNext(T t); public void onError(Throwable t); public void onComplete(); }
27. Publisher Subscriber Subscription
28. Publisher Subscriber Subscription public interface Subscription { public void request(long n); public void cancel(); }
29. Publisher Subscriber Subscription public interface Subscription { public void request(long n); public void cancel(); }
30. Publisher Subscriber Subscription
31. Processor Publisher Subscriber Subscription
32. Publisher Subscriber Subscription Processor public interface Processor<T, R> extends Subscriber<T>, Publisher<R> {}
33. Example
43. Project Reactor
44. by
45. RxJava-like API
46. Reactive Types
47. Flux
48. like Stream<T>
50. Mono
51. like CompletableFuture<T>
53. Useful Operators
54. Operator == Very Smart Publisher
55. merge .merge(…)
56. zip .zip(…)
57. zip .zip(…)
58. publish .publish(…)
59. .materialize(…) materialize
60. materialize .materialize(…)
61. Thread A Thread Main .publishOn(…) publishOn
63. RxJava.observeOn == Reactor.publishOn
64. Remember!
65. Nothing happens until .subscribe ()
66. Reactivity in Action
67. What we`re going to do?
68. Refactoring
69. What do we have?
70. Chat Application
71. Functionality • Gitter Chat Communication • Messaging Statistic
72. Demo
74. Toolkit • Spring Framework 4 • Spring Boot • Spring MVC • Spring Data JPA
75. Architecture
76. User Client Gitter Service Whole Application DB Layer Service Layer Controllers Layer
77. Controllers Layer
78. Returns Thymeleaf View
79. REST Resources
80. Services Layer
81. External Chats SPI
82. Domain Services
83. Gitter integration
84. Implementation
85. Persistence Layer
86. Database Model
87. How it works?
92. Problems
93. Problems • Pulling model
95. Problems • Pulling model • Too much blocking I/O
96. Solutions
97. Apply Reactive Manifesto
99. Async Messaging Push Model
100. Apply Streaming API
103. Async Messaging Elasticity
104. Dedicate ThreadPool
107. Async Messaging Push Model
108. Apply WebSocket
110. How to bring it all together?
111. Spring 5
112. Painless replacement
113. WebFlux @Controller, @RequestMapping,… Spring MVC Servlet API Servlet Container Spring Web Reactive Reactive HTTP Servlet, Netty, Undertow
116. @RestController @RequestMapping("/api/v1/statistics") public class StatisticResource { private final StatisticService statisticService; @Autowired public StatisticResource( StatisticService statisticService) { this.statisticService = statisticService; } @GetMapping("/users") public List<UsersStatisticVM> getUsersStatistic() { return statisticService.getUsersStatistic(); } }
117. @RestController @RequestMapping("/api/v1/statistics") public class StatisticResource { private final StatisticService statisticService; @Autowired public StatisticResource( StatisticService statisticService) { this.statisticService = statisticService; } @GetMapping("/users") public List<UsersStatisticVM> getUsersStatistic() { return statisticService.getUsersStatistic(); } }
118. @RestController @RequestMapping("/api/v1/statistics") public class StatisticResource { private final StatisticService statisticService; @Autowired public StatisticResource( StatisticService statisticService) { this.statisticService = statisticService; } @GetMapping("/users") public Flux<UsersStatisticVM> getUsersStatistic() { return Flux.fromIterable(statisticService .getUsersStatistic()); }
119. @RestController @RequestMapping("/api/v1/statistics") public class StatisticResource { private final StatisticService statisticService; @Autowired public StatisticResource( StatisticService statisticService) { this.statisticService = statisticService; } @GetMapping("/users") public Flux<UsersStatisticVM> getUsersStatistic() { return Flux.fromIterable(statisticService .getUsersStatistic()); }
120. Project Reactor + Netty Integration
121. Why Netty?
122. Non-Blocking,Reactive Server
123. Reactive Architecture
124. Data Base Connection Pipe Gitter Connection Pipe
125. Refactoring Structure
126. 1. Blocking I/O Refactoring 2. Service Refactoring 3. Endpoints Refactoring 4. Pipeline Testing
128. Blocking I/O Refactoring
130. Reactive DB Access via ReactiveCrudRepository<T, ID>
131. interface ReactiveCrudRepository<T, ID> extends Repository<T, ID> <S extends T> Mono<S> save(S entity); <S extends T> Flux<S> saveAll(Iterable<S> entities); <S extends T> Flux<S> saveAll(Publisher<S> entityStream); Mono<T> findById(ID id); Mono<T> findById(Mono<ID> id); Mono<Boolean> existsById(ID id); Mono<Boolean> existsById(Mono<ID> id); Flux<T> findAll(); Flux<T> findAllById(Iterable<ID> ids); Flux<T> findAllById(Publisher<ID> idStream); Mono<Long> count(); Mono<Void> deleteById(ID id); Mono<Void> delete(T entity); Mono<Void> deleteAll(Iterable<? extends T> entities); Mono<Void> deleteAll(Publisher<? extends T> entityStream); Mono<Void> deleteAll(); }
132. interface ReactiveCrudRepository<T, ID> extends Repository<T, ID> <S extends T> Mono<S> save(S entity); <S extends T> Flux<S> saveAll(Iterable<S> entities); <S extends T> Flux<S> saveAll(Publisher<S> entityStream); Mono<T> findById(ID id); Mono<T> findById(Mono<ID> id); Mono<Boolean> existsById(ID id); Mono<Boolean> existsById(Mono<ID> id); Flux<T> findAll(); Flux<T> findAllById(Iterable<ID> ids); Flux<T> findAllById(Publisher<ID> idStream); Mono<Long> count(); Mono<Void> deleteById(ID id); Mono<Void> delete(T entity); Mono<Void> deleteAll(Iterable<? extends T> entities); Mono<Void> deleteAll(Publisher<? extends T> entityStream); Mono<Void> deleteAll(); }
133. Code session
134. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
135. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
136. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
137. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
138. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
139. .publishOn() public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); }
140. public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); } .publishOn()
141. public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); } .subscribeOn() MonoProcessor
142. public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); } .subscribeOn() MonoProcessor
143. public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); } MonoProcessor .subscribeOn() …subscribe();
144. public static <S, V> Mono<V> mono( Mono<S> input, Function<...> transformer ) { MonoProcessor<V> monoProcessor = MonoProcessor.create(); input .publishOn(Schedulers.elastic()) .transform(transformer) .subscribe(monoProcessor); return monoProcessor .subscribeOn(Schedulers.elastic()); } …subscribe(); MonoProcessor .subscribeOn() …subscribe();
145. Service Refactoring
146. Gitter Service
147. Reactive WebClient out of the box
148. public interface WebClient { UriSpec<RequestHeadersSpec<?>> get(); //omitted... static WebClient create() { return new DefaultWebClientBuilder().build(); } interface RequestHeadersSpec<S extends RequestHeadersSpec<S>> { //omitted... Mono<ClientResponse> exchange(); //omitted... } interface ResponseSpec { <T> Mono<T> bodyToMono(Class<T> bodyType); <T> Flux<T> bodyToFlux(Class<T> elementType); <T> Mono<ResponseEntity<T>> toEntity(Class<T> bodyType); <T> Mono<ResponseEntity<List<T>>> toEntityList(Class<T> element } }
149. public interface WebClient { UriSpec<RequestHeadersSpec<?>> get(); //omitted... static WebClient create() { return new DefaultWebClientBuilder().build(); } interface RequestHeadersSpec<S extends RequestHeadersSpec<S>> { //omitted... Mono<ClientResponse> exchange(); //omitted... } interface ResponseSpec { <T> Mono<T> bodyToMono(Class<T> bodyType); <T> Flux<T> bodyToFlux(Class<T> elementType); <T> Mono<ResponseEntity<T>> toEntity(Class<T> bodyType); <T> Mono<ResponseEntity<List<T>>> toEntityList(Class<T> element } }
151. Code Session
152. @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); }
153. @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); } .onBP()
154. @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); } .onBP()
155. .onBP() @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); }
156. .onBP() @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); }
157. .onBP() @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); }
158. .onBP() @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); } …subscribe();
159. .onBP() @Autowired public GitterService( GitterClient gitterClient ) { gitterMessageSource = Flux.from( gitterClient .getMessages(null) ) .onBackpressureBuffer() .publish(1) .autoConnect(0); } …subscribe(); …subscribe();
160. Message Service
162. Code Session
163. @Override public Flux<MessageVM> latest() { return chatClient.stream() .transform(MessageMapper ::toViewModelUnits ); } @Override public Flux<MessageVM> latest() { return chatClient.stream() .transform(MessageMapper ::toViewModelUnits ); } @Override public Flux<MessageVM> latest() { return chatClient.stream() .transform(MessageMapper ::toViewModelUnits ); } .transform()
164. Statistics Service
166. Code Session
167. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); }
168. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
169. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
170. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } Channel .materialize()
171. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
172. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
173. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
174. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform()
175. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .materialize() .transform()
176. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .transform() .materialize()
177. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } Channel .materialize()
178. Channel @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .materialize()
179. @Autowired public DefaultMessageService( MessageRepository messageRepository, ChatService<MessageResponse> chatClient, MessageBroker messageBroker ) { this.chatClient = chatClient; Flux<Message> saved = messageRepository .saveAll(chatClient.stream() .transform(MessageMapper::toDomainUnits) ); messageBroker.createChannel( "statisticChanged", saved.materialize() ); } .materialize() Channel
180. Code Session
181. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
182. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
183. .retry() Channel this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
184. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
185. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
186. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
187. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
188. .retry() Channel this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
189. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
190. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
191. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel
192. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() Channel .dematerialize()
193. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); Channel .retry() .dematerialize()
194. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) .mergeWith .defer(statistic)
195. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) .mergeWith .defer(statistic) …subscribe();
196. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) .mergeWith .defer(statistic) …subscribe();
197. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) …subscribe(); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .mergeWith .defer(statistic)
198. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) …subscribe();
199. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) …subscribe();
200. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .flatMap() .cache(1) …subscribe();
201. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); …subscribe(); .flatMap() .cache(1)
202. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); Channel .retry() .dematerialize()
203. this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1); .retry() .dematerialize() .flatMap()
204. .retry() .dematerialize() .flatMap() this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
205. .dematerialize() .flatMap() .cache(1) this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
206. .dematerialize() .flatMap() .cache(1) this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
207. .flatMap() .cache(1) this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
208. .flatMap() .cache(1) this.statisticPublisher = messageBroker .channel("statisticChanged") .retry(err -> err instanceof USE) .dematerialize() .flatMap(s -> doGetUserStatistic()) .mergeWith(Mono .defer(this::doGetUserStatistic) ) .cache(1);
209. Code Session
210. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
211. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
212. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
213. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
214. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
215. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
216. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
217. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
218. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
219. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
220. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
221. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null null
222. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
223. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
224. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…) null
225. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .map(…) .defaultIfEmpty(…) .zip(…)
226. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
227. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
228. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
229. private Mono<UsersStatisticVM> doGetUserStatistic Flux<UserVM> topActiveUser = userRepository .findAllOrderedByActivityDesc(PageRequest.o .map(UserMapper::toViewModelUnits); Flux<UserVM> topMentionedUser = userRepository .findAllOrderedByMentionDesc(PageRequest.of .map(UserMapper::toViewModelUnits); return Mono.fromDirect( Flux.zip( topActiveUser.defaultIfEmpty(EMPTY_USER), topMentionedUser.defaultIfEmpty(EMPTY_USER) UsersStatisticVM::new ) ); } .defaultIfEmpty(…) .zip(…) .fromDirect(…)
230. Endpoints Refactoring
232. Reactive WS out of the box
233. public interface WebSocketSession { String getId(); HandshakeInfo getHandshakeInfo(); DataBufferFactory bufferFactory(); Flux<WebSocketMessage> receive(); Mono<Void> send(Publisher<WebSocketMessage> messages); default Mono<Void> close() { return close(CloseStatus.NORMAL); } Mono<Void> close(CloseStatus status); WebSocketMessage textMessage(String payload); WebSocketMessage binaryMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pingMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pongMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); }
234. public interface WebSocketSession { String getId(); HandshakeInfo getHandshakeInfo(); DataBufferFactory bufferFactory(); Flux<WebSocketMessage> receive(); Mono<Void> send(Publisher<WebSocketMessage> messages); default Mono<Void> close() { return close(CloseStatus.NORMAL); } Mono<Void> close(CloseStatus status); WebSocketMessage textMessage(String payload); WebSocketMessage binaryMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pingMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pongMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); }
235. public interface WebSocketSession { String getId(); HandshakeInfo getHandshakeInfo(); DataBufferFactory bufferFactory(); Flux<WebSocketMessage> receive(); Mono<Void> send(Publisher<WebSocketMessage> messages); default Mono<Void> close() { return close(CloseStatus.NORMAL); } Mono<Void> close(CloseStatus status); WebSocketMessage textMessage(String payload); WebSocketMessage binaryMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pingMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); WebSocketMessage pongMessage( Function<DataBufferFactory, DataBuffer> payloadFactory); }
236. Code session
237. @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network .merge()
238. @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network .merge()
239. @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network .merge()
240. @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network .merge()
241. .merge() @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network
242. network .merge() @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); }
243. network .merge() @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); }
244. @Override public Publisher<?> handle( Publisher<Object> in ) { return Flux.merge( messageService.latest(), statisticService .usersStatisticStream() ); } network .merge()
245. Pipeline Testing
246. StepVerifier
247. StepVerifier .create(myPublisher) .expectNext(“x”, “y”) .expectComplete() .verify();
248. StepVerifier .create(myPublisher) .expectNext(“x”, “y”) .expectComplete() .verify();
249. StepVerifier .create(myPublisher) .expectNext(“x”, “y”) .expectComplete() .verify();
250. StepVerifier .create(myPublisher) .expectNext(“x”, “y”) .expectComplete() .verify();
251. StepVerifier .create(myPublisher) .expectNext(“x”, “y”) .expectComplete() .verify();
252. Code session
253. Demo
255. Checkpoints • Message Driven • Resilient • Responsive • Elastic
256. SUMMARY
257. Q&A
258. Resources 1. Why Reactive? [http://www.oreilly.com/programming/ free/why-reactive.csp] 2. Operator Fusion Part 1 [http://akarnokd.blogspot.com/ 2016/03/operator-fusion-part-1.html] 3. Reactive Streams Specification [http://www.reactive- streams.org/] 4. Learn Project Reactor [http://projectreactor.io/learn]
259. Thank you!